Visual impairment and the prevalence of ocular pathology in homeless children and adults globally: a systematic review

Background: Homelessness is a global issue in developing and developed countries. This article is the first systematic review to explore its impact on visual health globally. Methods: A systematic literature search was conducted on OVID MEDLINE, EMBASE, and Cochrane CENTRAL. Peer-reviewed English-language studies with a focus on homeless children or adults that reported on ocular outcomes were included. Primary outcomes and secondary endpoints were reported via weighted averages. Primary outcomes between homeless children and homeless adults were compared using the Fisher exact test. Results: There were 5774 individuals across 23 full-text articles included in the review. For studies reporting primary outcomes, 36.8% of homeless individuals self-reported dissatisfaction with their vision, 26.8% self-reported a previous ocular pathology, 26.3% had uncorrected refractive error, 25.6% were functionally visually impaired, 9.2% had at least one previous eye surgery or procedure, and 4.0% had nonrefractive visual impairment. Upon screening, 25.1% of homeless individuals had some type of ocular pathology, which included cornea and external eye diseases (13.4%), glaucoma (7.4%), cataracts (6.3%), retinal diseases (5.3%), ocular motility disorders (4.7%), trauma (2.3%), neuro-ophthalmological conditions (1.7%), and oculoplastic conditions (0.7%). Homeless adults had significantly more visual impairment (p < 0.001), uncorrected refractive error (p < 0.001), ocular pathology (p < 0.001), cataracts (p < 0.001), retinal pathology (p < 0.001), and neuro-ophthalmological conditions (p < 0.001) relative to children. Conclusions: Visual impairment in homeless individuals is higher than the general population. Uncorrected refractive error is a leading cause of visual impairment in this population. Additionally, homeless adults have significantly more visual impairment and ocular pathology than homeless children. Future studies should also explore if these differences are consistent in developing countries and investigate ways to increase eye care access for homeless individuals.